Model-based recognition and positioning of polyhedra using intensity-guided range sensing and interpretation in 3-D space

Abstract

This paper presents a design of 3-D multi-sensory (visual and ranging) system capable of identifying and locating polyhedral objects in six degrees of spatial freedom. Due to differences in sensor characteristics, e.g. the fast data acquisition in intensity domain and the abundance of information inherent in range domain, sensors should operate in a cooperative manner to increase system efficiency and to yield information otherwise unavailable, or hard to obtain, from any single sensor. The adopted strategy of intensity-guided range sensing firstly extracts features (e.g. the line drawing and the “control points”) from intensity images and then uses them as a guide to selectively sense ranges. Through the interfusion of both types of information, 3-D object description in terms of a relational graph structure is thus constructed for recognition and positioning purposes. To identify the object, interpretation tree search in 3-D space is applied to the matching between the constructed relational graph and those stored in database. Since high level primitives (such as faces) derived from intensity and range informations are utilized for interpretation (or, matching), the search space can be significantly reduced. Finally, a non-iterative method based on the quaternion technique is adopted to solve the transformation between sensor and model coordinates for further robotic applications.